radius
UK: ˈreɪdiəs | US: ˈreɪdiəs
n. a straight line from the center to the circumference of a circle or sphere
n. the thicker and shorter of the two bones in the human forearm
n. a specified distance or range from a central point
The word "radius" originates from Latin radius, meaning "spoke of a wheel" or "ray of light." This reflects its geometric sense as a line extending from a central point, akin to spokes radiating from a wheel's hub. The anatomical use (forearm bone) derives from its resemblance to a spoke. The term entered English in the 16th century, retaining its core idea of linear extension from a center.
The radius of the circle measures exactly 5 centimeters.
She fractured the radius in her left arm during the fall.
The explosion affected everything within a 10-mile radius.
The artist drew radii from the center to create a symmetrical design.
The hospital serves patients within a 50-kilometer radius.